Loud-speaking transmitter.



J. G. R. PALMER & A. P. PINKLER.

LOUD SPEAKING TRANSMITTER.

APPLICATION I'lLBD NOV.13, 1911.

1,1 17,231 Patented Nov. 17, 1914.

Fig.

Unirn stares arena: anion Jenn c. n. PALMER, or BROOKLYN, new YORK, AND ARTHUR r. rnvntnn, or WEE- HAWKEN, NEW JERSEY, ASSIGNORS TO wns'rnnu ELECTRIC COMPANY, or NEW toner, n. Y., A CORPORATION or rumors.

LOUD-SPEAKING TRANSMiTTER.

' mitting apparatus, and more particularly to a. telephone transmitter. for use where extr'emely long distance transmission is necessary.

The object of this invention is to provide a transmitter for use with high battery currents, in which the maximum current variation may be obtained with the minimum movement of the diaphragm, in which all .rirovable parts are free from outside strain or weight, in which the tendency of the resistance varying medium to ack is reduced to a minimum and in whic suitable provision may readily be made for heat radiation.

A further object of this invention is to so form the mechanical parts that they will be simple and few in number, of dura l itv which 'may be easily assembled, and will when assembled retain their positions of adjustment under severe service conditions.

One of the features of this invention therefore involvesth'e use of two fixed and two movable electrodes so related that in the movement of the movable electrodes pressure upon the resistance arying material is relaxed with respect to one fixed electrode, and simultaneously increased with respect to the other iiXed electrode. One

methodby which this may be accomplished is to mount the'movable electrodes in a cup carried by the diaphragm which cup also contains the fixed or stationary electrodes the end Walls of said cup being mica disks secured to permit the movement of said cup relative to the fixed electrodes.

Another feature of this invention relates to the method of mounting the diaphragm and fixed or stationary electrodes, and consists'i'n the provision of a vair of support- 1mg plates bet-ween which t e diaphragm is mounted, said plates being clamped together and adapted to receive adj ustahle support- Specification of Letters Patent.

e qual- Patented Nov. 17, 1934.

Application filed November 13, 1911. Serial No. 659,933. 1

ing members to which the stationary electrodes are secured.

Other features of the invention are th 3 is a circuit diagram illustrating the connection of the parts. p

A support or front piece 5 of any desired term carrying" a mouthpiece 6 is supported in a casing 7 i porting lu 8 by means of which the transmitter may be attached to a desk stand or subscriber set box. Located in the casing 7 is a supporting framework comprising front and back face plates 10 and 11 secured together by means of machine screws 12, 12. As shown the front face late 10 is recessed in its face to receive a iaphragm 15 and clamping rings 16', 16, and is cupped to form a resonating chamber 17. A reduced cylindrical portion 18 of said face plate 10 is provided at its outer end with screw threads adapted to engage interior screw threads in an annular projection 19 formed upon the front piece 5. The resonating chamber 17 is open to the air only through the mouthpiece 6 as the operation of the diaphragm is dependent upon the air vibrations set up in the resonating chamber. The clamping rings 16, 16 are formed of thin resilient metal sen'iicircular in cross section and these rings and the diaphragm are electrically separated from the plate 10 by means of in sulating rings 20, 21 preferably of mica.

'An insulatingring 22 is-.also insertegl betion '25 thereon corresponding with the portion 18 upon the plate 10. The reduced portions 18.21nd'25 are bored to receive metal cylinders-3Gand 31 for supporting station ary electrodes 32, 32 as'will more fully here inafter appear.

aving attached thereto a sup-.

Referring now to the method of mountingthe electrodes this comprises features of construction as follows: Located in the-con: 'ter ofthle diaphragm 15 is a cylindrical screw, threaded casing 39 having two bores 40 and 41 of diii -erent' diameters, which meet near the center of said casing to formashoulder 42. Located within said casing '39 and abutting against the shoulder is a metal disk 43 having secured to its opposite faces carbon electrodes 1-4, 4:4. Inserted in the bore of larger diameter and bearing against the metal disk L-3 is an insulating ring 4-5 ofthe same interior diameter as the bore &0. The outer end of the ring 45 is having a shouldered portion 51- against which the diaphragm 15 is clamped by means of a clamping ring Screws 53, 53 are inserted in said lugs for securing terminals thereto. Clamped upon the front end ofthe casing 39 by means of a clamping ring 5 1s a mica diaphragm ,55 which forms, with said casing and the mica diaphragm 26, an inclosed chamber. In addition to the electrodes e4, e4: whichconstitute the movable electrodes of the transmitter there are located in the chamber upon opposite sides of the metal disk 43 the electrodes 32, 32. These electrodes 32, 32 constitute the fixed electrodes of the transmitter and are secured to screw threaded studs 61, 61 which extend through thcmica diaphragrns 46 and into screw threaded openings in the cylinders 30 and 31. The cylinders 30 and 31 are adjustably secured in the portions 18 and 25 of the electrodes. In the space within the casing 39 not occupied by the electrodes, aresistance varying medium is placed which may be comminuted carbon. lVhen the diaphragm is vibrated the pressure upon the resistance varying medium is relaxed with respect to one fixed electrode and simultaneously increased with respect to the other fixed electrode.

Sound vibrations are led into the resonating chamber 17 from the mouthpiece 6 through a plurality of circumferentially ar ranged openings 70, through the reduced portion 18 of the face plate 10. These openings 70, 70' are surrounded by the mouthpiece 6 and a roundnose deflecting member is secured in the outer end of the cylinder 30. This deflecting member, which is located within the circle of the openings 70, 70 extends into the mouthpiece 6 and serves to deflect the sound vibrations into the circumierentially arranged openings.

Mounted. upon the portion 18 of the plate 1.0 betweenthe outer face thereof and inner face of the front piece, 5 are heat re Alined openings 84;, 85 and 86 are provided I in the terminal plate, rear set of fins 80,. and plate 11 respectively for leading circuit wires into the connecting screws 53, 53 in thelugsfiO, 50 of the casing 39. The main casing 7 is secured to the front piece 5 by means ofscrews 88, 88 andis provided with two rows of openings 90,90 opposite the two sets of radiating fins orplates forpeiwmitting the dissipation of the heat into the outer air. I

By mounting the movable electrodes upon the diaphragm in the manner described the weight of all movable parts, is removed from'said electrodes, thus avoiding the inertia of heavy connecting members and permitting the electrodes to vibrate freelyin re-" sponse tothe viorations of the diaphragm and to readily assume a state of equilibrium when the parts are inactive. The mounting of the diaphragm between the two plates 10 and 11 which are clamped together and sup ported entirely upon the front piece 5 pro. rides a structure which may be easily assembled and in which the parts are readily accessible. The use of the metal. clamping rings for the diaphragm is of advantage in a sti icture of this kind inasmuclras they are practically unailected by the temperature changes occurring in the operation of the transmitter with large currents as would not be the case if rubber ringswere used,

nor are they affected by other atmospheric conditions to the extent that the rubber would be.

By insulating the front and back plates from each other and the diaphragm from the plates a convenient mcans is provided for n'iaking the connections for the circuit which is as shown in Fig. 3. In this diagram the conductor 94 from battery 91 is connected to the diaphragm through the lugs 50, 50, the conductor 92 to the back stationary electrode 32 by way of the terminal block 82, and the conductor 93- with the front stationary electrode through the casing.

o claim:

1. In a telephone transmitterthe-comhination with a sound receiving diaphragm, of a granules containing cup carried by said diaphragm, a pair of stationary electrodes located in said cup, 21 second pair of electrodes carried by said cup to vibrate between said fixed electrodes and a resistance varying medium in said cup between said fixed and movable electrodes.

2. In a telephone transmitter, the combination with a sound receiving diaphragm, of a granule containing cup carried by said diaphragm, a pair of stationary electrodes located in opposite ends of said cup, :1. second pair of electrodes disposed back to back and mounted centrally of said cup to vibrate therewith, and a resistance varying medium in said chamber between said stationary and movable electrodes.

3. In a telephone transmitter the combination with a sound receiving diaphragm, "of a ringsecured in said diaphragm and having two bores of diiferent diameter meeting near the center of said ring to form a shoulder, a metal disk clamped against said shoulder, carbon electrodes secured to the opposite faces of said disk, stationary electrodes located at the ends of said ring, and

a resistance varying medium betweeer the stationary electrodes and the electrodes carried by said disk.

4. In a telephone transmitter, the combination with a sound receiving diaphragm, of a metal ring secured in said diaphragm and having two hores of different diameter meeting near the center of said ring to form a shoulder, a metal disk abutting against said shoulder, electrodes mounted upon opposite faces of said disk, an insulating ring of the same interiordiameter as the smaller bore located in the lar er bore and bearing against said metal dis mica diaphragms clamped to the ends of said metal ring, one of said mica diaphragms serving to hold said insulating ring in place, stationar electrodes on opposite sides of said meta disk and a resistance varying medium between said stationary elctrodes and the electrodes carried by said metal disk.

5. In a telephone transmitter the combination with a sound receiving diaphragm of a screw threaded metal ring, lugs thereon abutting against one side of said diaphragm, a screw threaded securing ring thereon hearing against the opposite face of said diaphragm, stationary electrodes located at opposite ends of said ring, movable electrodes located centrally of said ring to vibrate therewith, and a resistance varying medium between said movable and stationary electrodes.

6. In a telephone transmitter the combination with a sound receiving diaphragm of supporting plates between which said diaphragm is mounted, movable electrodes supported by said diaphragm, adjustable members carried by said plates and stationary electrodes carried by said adjustable members to coiiperate with said movable electrodes.

7. In a telephone transmitter the combi- -s ee mai nation with a diaphragm, of face plates be tween which said diaphragm is clamped, a reduced cylindrical portion upon each of said plates having an opening therein, a metal cylinder adjustably supported in each of said openings, movable electrodes carried by said diaphragm, and stationary electrodes mounted upon said metal cylinders to coiiperate with said movable electrodes.

8. In a telephone transmitter the combination with two metal face plates, one of which is cupped to form a resonating chamber, of a metal diaphragm responsive to sound waves clamped between said plates, a reduced cylindrical portion on one of said plates having openings leading into said resonating chamber, a mouthpiece located adjacent the outer end of said openings and a sound deflecting member located in said mouthpiece.

9. In a telephone transmitter the combination with tWo metal face plates, one of which is cupped to form a resonating chamber, of a diaphragm responsive to sound waves clamped between said plates, a .reduced cylindrical portion one of said plates havingya plurality of circumferentially arranged o enings leading into said resonating chain er, a mouthpiece supported'adjacent t e outer end of said openings, and a sound deflecting member supported by said reduced cylindrical portion.

10. In a telephone transmitter the combination with a front piece of two metal face plates clamped together and supported upon said front iece, one of said plates being cupped to orm a resonating chamber and having openings leading into said chamber, a diaphragm responsive to sound waves clamped between said plates, a mouthpiece secured to said front piece and surrounding said openings, and a sound deflecting member located in said mouthpiece within the circle of said openings. 4

11. In a telephone transmitter, the combination with a diaphragm responsive to sound waves, of movable electrodes carried thereby, metal face plates between which said diaphragm is clamped, stationary electrodes carried by said face plate to cooper ate with said movable electrodes, a reduced portion upon each of said metal plates and heat conducting fins secured to said reduced portions.

In witness whereof. we hereunto subscribe our names this 8th day of November A. D., 1911.

JOEL C. R.- PALMER. ARTHUR l. PINKLER. -Witnesses:

IRVING MACDONALD. F; P. Mcln'rosn. 

